1. Field of the Invention
The present invention relates to a static mixer for mixing components of liquid reactive multicomponent compounds and including a jacket having a mixing section, an inlet and an outlet, and at least one mixing element arranged in the mixing section and having its outer dimensions adapted to inner dimensions of the jacket. The present invention also relates to the use of the static mixer for introducing additives that influence physical and/or chemical characteristics of a liquid mixture produced of liquid reactive components forming a multicomponent compound.
2. Description of the Prior Art
Liquid reactive multicomponent compounds are used in diverse ways as, e.g., two-component glues, two-component mortar masses for securing structural components, anchor rods and the like in solid constructional grounds such as brickwork, concrete or similar hard bases, or for forming fire-protection foams or constructional foams used for filling of breakthroughs, leadthroughs, and openings in walls, ceilings, and floors of buildings or for forming of windows or doors of buildings. Such multicomponents compounds, in particular, those used on a building site, are usually available in multi-chamber containers or vessels in which components that react with each other, are stored separate from each other, without a possibility of a reaction therebetween. During use, the different components are fed from the separate containers, e.g., by being squeezed-out with an ejector device, and are mixed with each other. Thereafter, the mixture is introduced into the use region, e.g., a dowel bore.
Finally, the fastening components are introduced, e.g., an anchor rod is inserted in the dowel bore filled with the mixture. Then, hardening of the compound, which is obtained by intermixing of the components, takes place.
In a region, which is thermally insulated from buildings, metering apparatuses are used for spraying onto walls and roofs large-surface insulating foam sheets. To this end, there is provided, in the front region of a spray gun, caps with which separate components of multicomponent insulating foamed compounds are mixed with each other.
For mixing different components of compounds, usually static mixers are used in which there is arranged, in a jacket, a mixing element that provides for a homogeneous intermixing of components of a mixture by using the flow energy of the components of a multicomponent compound which are fed into the static mixer under pressure. Here, mixing devices are used that have either a movable container or a movable mixing tool and in which intermixing of the mixture takes place as a result of the effect of the movement energy of the mixture that continuously flows through the static mixer, with the mixing element or elements, which are located in the flow path, effecting an intensive intermixing of the mixture. As mixing elements, manifolds, expansion elements, injectors, counterflow conduits, swirling elements, guide plates, inserts of different types, which provide for an intensive intermixing due to their shape, are used.
Both the jacket and the mixing elements of such static mixers can be formed of different materials, e.g., metal, glass and, in particular, plastic materials. In particular, removable mixing elements of different shapes, which are used for intermixing and feeding of the multicomponent compounds in form of mortar mass, constructional foam, etc., are formed of a plastic material.
Mixers, which are used for intermixing of multicomponent compounds which are produced in form of mortar masses, constructional foams, fire protection foams, etc. at a constructional site before using them at a point of use, are generally available in form of disposable plastic static mixers having a jacket, mixing elements, which are arranged therein, with a static mixer being mountable on the outlet of an ejector tool. After a static mixer is fixed on the ejector apparatus or tool, the components of a multicomponent compound, which are stored in separate containers, are squeezed out under pressure either by mechanical means or using a pressure fluid or other drive means, from the separate containers, and are delivered through the mounted on the ejector apparatus, static mixer.
When such multicomponent compounds are used at a location of use, e.g., for filling openings, there is often exist a problem that consists in that the mixture, which is delivered out of the mouthpiece of the static mixer and in which hardening or foaming reactions take place, does not have yet a required viscosity after having been brought to the point of use, e.g., on the roof or transverse walls, and the mixture flows out of the openings and down the walls. Usually, in order to prevent the compound from flowing out, boards of cardboard which are secured to the underside of a roof or a wall with a scotch tape, are used. Also, in the region of openings or dry walls, boarding which is made of wire mesh or rib mesh and which is bent so that it is adapted to a respective opening, is used. Obviously, the use of boarding in order to prevent flow-out of a multicomponent compound is associated with additional operational steps and, accordingly, with increased costs.
It is further known to so modify a mortar mass and, in particular, foams, which are made of multicomponent compounds, with chemical or physical thixotrope means that the mortar mass or the foam reaches a satisfactory “stability” even when their interreaction has not been completed. By using such thixotrope means, unloaded, low-density insulation foams can be produced with a sufficient stability. With loaded, high-density fire protection foams, increase of the viscosity by using the thixotrope means creates certain problems during squeezing of the components out as a result of their increased flow resistance.
It has been found out that the stability of two-component polyurethane foams, which are used as constructional foams, can be increased by adding of acrylate to the mixture. The increase of the viscosity is obtained as a result of the physical effect on reactions of polyurethane formation of breaking or dispersion of the acrylate in the mixture because of difference in polarity between isocyanate and the first component. This results in delay and thereby to an increase of the viscosity of the mixture.
The advantage of the breaking of the acrylate dispersion consists in that the mixture has, upon entering the mixer, a smaller viscosity which is increased slowly as the mixture passes through the mixer. As a result, a smaller force is required for squeezing the mixture out of the mixer. When the foam leaves the static mixer, it has a sufficiently high adhesiveness for adhering to a wall, and a viscosity that prevent the flow of the mixture out of openings or down a wall.
The drawback of the above-discussed effect of breaking of the acrylate dispersion in a two-component-polyurethane-acrylate foam compound consists in that the polyurethane reaction depends in a large degree on a temperature. At high temperatures during the use of a compound, above 25° C., which usually exist in summer on a constructional site, there is a danger of the polyurethane formation reaction running more rapidly than breaking of the acrylate dispersion, with resulting increase in viscosity. This would not permit to achieve a desired effect of preventing the mixture from flowing out. As a result, the desired physical breaking of the dispersion becomes suppressed, and desired physical characteristics of the hardened foam are not achieved, e.g., because of a smaller density of the hardened material. It is also possible to vary the speed of the dispersion breaking by adding suitable additives to polyol components and to polyisocyanate components and mixtures produced in a static mixer. Generally, the increase of the speed of breaking of the dispersion is limited by a physical length of the mixer. When the speed of breaking of dispersion is too high, the dispersion in the static mixer fails completely, which result in that high forces need to be applied to deliver the mixture from the static mixer.
An object of the present invention is to provide a static mixer which would insure delivery of a liquid mixture formed of a liquid reactive multicomponent compound and physical and/or chemical characteristics of which can be purposely influenced in such a way that the required or desired characteristics are only achieved after the mixture leaves the mixer so that a small force is required for squeezing the mixture out of the mixer.
Another object of the present invention is a static mixer that would provide for rapid influence of the additives on physical and/or chemical characteristics of the mixture by insuring a good intermixing of the additives with the mixture, so that the mixture would have the desired physical and/or chemical characteristics immediately after being delivered from the outlet of the static mixer. This should insure that the produced, e.g., constructional foam has a high adhesive property, which would insure its good adherence at the predetermined point of use, and a required high stability, which would provide for a boarding-free placing of a foam on a wall and a roof.
A further object of the present invention is to provide a mixer with which it would be possible to select appropriate filler materials and to add them in a necessary amount to the mixture, before its use at a predetermined point of use, dependent on the expected environment conditions or on the required characteristics of the mixture.